Code : Katrina
by PhoenixReign
Summary: Ulrich's sister, Katrina went missing five years ago. What happens when Jeremie and Aelita discover that there's another person on Lyoko? Could it be Katrina? Or will Ulrich's hope of reuniting with his sister be in vein?
1. Prologue

It was an average day in the Stern residence. Katrina who was the eldest child was sitting in her room studying for her high school exams. She was a senior so passing these exams were important to her. Books were scattered across her desk with papers in between. She was completely focused until a knock on her door brought her back to reality. The door opened revealing her younger brother.

"Ugh what do you want Ulrich?" She asked annoyed with being interrupted during her study session.

"Can you help me with my pencak silat training?" He asked. Katrina was a brown belt while Ulrich was just a beginner. Because of this, Ulrich often asked his older sister to help him with his training. Unfortunately, he always asked during the most inconvenient times like this one.

"I'm busy" She responded refocusing on her studies.

"What a surprise" Ulrich muttered sarcastically before leaving closing the door behind him. Katrina heard him and simply rolled her eyes in response. Now it was dinner time. As much as Katrina claimed she wasn't hungry, her father insisted she eat with the family.

"Ulrich, care to explain why you're still failing math?" Their father questioned sternly as he wiped his face with his napkin.

"Because it's hard" Ulrich simply replied not making any eye contact with his father.

"This is unacceptable Ulrich" He stated giving his son a serious look even though Ulrich was looking down at his plate. "Katrina you seem to be doing well in math. From now on I want you to tutor your brother" He continued turning to his daughter.

"Yeah, that's not happening" She stated as she stabbed a bite of food with her fork and ate it.

"Trina I wasn't asking" Their father noted.

"I have my own studying to do. I got exams coming up" She argued.

"You're a straight A student and Ulrich is failing" he stated in response.

"Oh, so I have to drop what I'm doing to tutor someone who can't be bothered to study on his own" She said annoyed with her father.

"Trina dear calm down" Her mother chimed sensing her daughter's frustration. She then turned to her husband. "Honey I don't think it's fair to have Trina tutor Ulrich when she has plenty of studying to do on her own" She said trying to reason with him.

"Fine then, if Ulrich fails again then they're both grounded" he announced. Katrina choked on her drink that she just sipped.

"What? You're kidding right?" She questioned in disbelief.

"Since you refuse to tutor your brother, you get punished as well" he explained. Frustrated with her father, Katrina got up from her seat throwing her napkin on the table and stormed away. The rest continued eating in silence. Ulrich felt pressured now. He had to pass his next math test, or not only will he get in trouble, but his sister as well.

Later that night Ulrich was up in his room. He sat on his bed with his math textbook in his hands and a notebook sitting next to him. There was a knock on the door and Katrina entered his room.

"Hey, can we talk?" She asked. Ulrich turned off the Subdigital music he had playing. Katrina walked in the room and sat at his desk chair.

"I'm sorry you got dragged into this Nina" Ulrich said. Nina was how Ulrich used to pronounce his sister's name when he was younger and could barely talk. Now it was just a nickname that only he referred to her as.

"Listen, I'm going to make a deal with you" She told him.

"What kind of deal?" he asked.

"You know how you always ask me to help you with your pencak silat training?" She inquired. Ulrich has a vague idea of where she was going with this.

"Yeah" he responded.

"Alright, well if you pass your next math test with at leas will spend the day giving you a pencak silat lesson" She offered. Ulrich's eyes lit up, yet he was still somewhat skeptical.

"You promise?" He questioned. She would always say she would, but they usually wind up being empty promises. Katrina nodded her head. She was probably only doing this because she would get mad at him if she got grounded because of him. Still, it gave him more motivation to study.


	2. Chapter 1

During the summer Katrina decided to do an internship at a local computer laboratory. She worked there five days a week for only 4 hours. One day she didn't return home. Her mother called her cell phone, but she never picked up. She then called the lab. The person on the other end claimed that they didn't know where she was. Her parents panicked calling the police to report her missing. The police conducted an investigation that eventually turned cold. The Stern family feared they would never see Katrina ever again.

Five years later Ulrich was now boarding at Kadic Academy. He was hanging out flipping through an old scrap book that his sister made of them years ago. His roommate Odd entered the room after walking his dog Kiwi.

"Hey Ulrich, whatcha got there?" Odd asked noticing the book he was flipping through.

"An old scrapbook my sister gave me" He answered with somber tone in his voice.

"I didn't know you have a sister. How come you never mentioned her before?" Odd questioned.

"It's a difficult subject to talk about. You see, she went missing five years ago after she started this internship at some computer lab in town" Ulrich explained. Odd then sat on Ulrich's bed looking over taking a glance at the book seeing a picture of Ulrich and his sister.

"Hey you're sister's pretty" Odd commented. In another room Jeremy was on his computer with Aelita sitting on his bed with her laptop. He was running some codes while Aelita was monitoring Lyoko. Something came up on Aelita's screen. It was data of something unknown going on Lyoko.

"Hey Jeremie, take a look at this" Aelita told him as she got up and showed him what was on her screen. Jeremy seemed perplexed by this.

"Hmm that's strange. Don't think I've seen that before" He stated. He decided to download the information from Aelita's laptop onto a disc so he can upload it onto his computer. He examined the information then suddenly an activated tower appeared.

"There's an activated tower in the Desert sector" Jeremy stated.

"I'll call Yumi" Aelita announced. As Aelita was dialing Yumi's number the tower deactivated.

"Wait the tower just deactivated" Jeremy told her. Aelita was confused by this.

"by itself?" She questioned.

"Looks like it" He responded.

"We have some free time before class. Should we head to the factory and check it out?" Aelita suggested.

"Yeah that sounds like a good idea" Jeremy replied. The two head to the factory. Once there Jeremy sets himself up at the super computer and checks out what's happening on Lyoko.

He noticed that there were monsters in the desert section that were being destroyed by something, but he couldn't pin point what it was. He did some data mining and discovered that there was another person on Lyoko. They couldn't tell who the person was exactly. Just that it was in fact a person.

"How on earth did someone get virtualized onto Lyoko without us noticing?" Jeremy mumbled to himself as he continued typing.

"Do you think that person is responsible for deactivating the tower and destroying all those monsters?" Aelita questioned.

"Possibly" Jeremy responded.

"Shall I go to Lyoko and see if I could find this person?" She asked.

"No, it's too risky without the others here" He replied. "Although this person is incredible. They deactivated a tower before XANA had the chance to launch an attack" he then commented.

"So what should we do?" She questioned.

"You go back to the academy. Let the others know what's going on. I'll stay here and see if I could get more information" He responded. Aelita nodded and headed back to the academy. She met up with the others in the cafeteria and explained to them what her and Jeremy discovered.

"What? There's another person on Lyoko? How is that possible?" Yumi questioned.

"We have no idea yet. Before a tower was activated and it seems that this person deactivated it before XANA could attack" Aelita stated.

"But how come we've never noticed them before? Lyoko isn't exactly that big to not notice" Yumi questioned.

"We don't know. Jeremy is at the factory finding that out right now" She answered. Odd was busy scarfing down his lunch and Ulrich just sat there in silence.

"Is everything okay Ulrich?" Aelita then questioned.

"Peachy" He replied slightly mopey.

"He's been staring at a scrapbook all day cause he misses his sister" Odd chimed with a mouth full of food.

"I didn't know you had a sister" Yumi commented looking at Ulrich.

"I don't want to talk about it" Ulrich stated.

"Are you and your sister close?" Aelita asked.

"Not really, it's complicated" Ulrich answered.

"You should see the picture he has of her. She's too pretty to be related to a guy like Ulrich" Odd commented with a laugh.

"Can it Odd" Ulrich said with a growl.

"Let's hope that she's not as gloomy as you are" Odd commented as he continued to eat. After lunch was over the group headed to class. Jeremy decided to skip class to figure out who this person was and how they got on to Lyoko.


	3. Chapter 2

Jeremie and Aelita were back in at the factory trying to figure out who this mystery person on Lyoko was. So far after hours of data mining all they could find out was that it was a girl that carried similar codes to Aelita meaning she could deactivate towers and have access to the information in Sector Five. There wasn't much more information on the girl. Later that day Jeremie decided that he wanted to see if he could find this girl on Lyoko. He told the others to meet him at the factory for an important mission.

"So, what's this all about Einstein?" Odd questioned

"We're going to find this girl that's somewhere on Lyoko" Jeremie stated.

"Do you know where she is exactly?" Yumi asked.

"She's still somewhere in the desert section" He responded. The group minus Jeremie was virtualized onto Lyoko in the desert section. At the moment it seemed pretty vacant. No girl and no monsters. It would make sense that there were no monsters since there was no activated tower. However, the desert section was a pretty open place and fairly small so there should be really no trouble spotting a person. That was if they weren't hiding out in a tower.

"Jeremie, do you have an exact location on where she is?" Ulrich asked. "We don't see anyone here" He then added.

"Hold on, give me a moment" Jeremie spoke as he tried to pin point her location. "According to the data on the map she's Southeast from where your location" He then answered after finding her exact location. "She's currently on the move though so you better hurry" He added noticing that her icon was moving on the screen.

"You mind sending us some vehicles?" Odd requested. Jeremie did as requested and sent them their vehicles. "Hey Ulrich, imagine if this mystery girl turns out to be your sister" Odd joked.

"Shut up Odd that's not funny" Ulrich stated in no mood for his jokes.

"Oh, lighten up will ya" Odd responded then moving ahead of him. Then soon an activated tower appeared on Jeremie's screen. Luckily it was located in the desert sector.

"Guys forget about the girl for now. A tower just activated west for where you guys are now" Jeremie announced. The group abandoned their mission and headed straight for the activated tower. "There's a swarm of hornets and a group of crabs heading your way" Jeremie warned noticing the monsters appearing on the screen. Odd managed to take out two hornets with his laser arrows and Ulrich defeated one crab. Yumi focused on getting Aelita to the tower while blocking attacks with her fan. Then suddenly several of the hornets were taken out at once. Odd had caught up to Yumi and Aelita so they thought it was him who did it.

"Well done Odd" Aelita praised.

"That wasn't me" Odd responded confused to who took out the hornets himself.

"Well it wasn't me or Ulrich. I wonder who did it?" Yumi questioned confused.

"Look ahead of you. It's the mystery girl" Jeremie voiced. The group looked head and sure enough, there she was. She was tall with brown hair that was pulled into a bun with her bangs hanging loose and a black headband that matched the black and green suit she was wearing with silver armor around her chest. She leaped over a crap shooting it in the target with her laser pistol causing the crab to explode. Ulrich immediate recognized the girl. Odd was right, it was his sister.

"I don't believe it. Odd was right. It is her" Ulrich commented in disbelief after joining the others.

"What? I was kidding. I didn't think it would actually be her" Odd noted. After she defeated the crab, she ran into the tower to deactivate it.

"I'll say, she has impeccable timing. She's deactivating towers before XANA is able to launch an attack" Jeremie stated. After the tower was deactivated, she exited the tower and was greeted by the group.

"Umm hello. Who are you guys?" She asked.

"Nina…?" Ulrich called out to see if it was really her or if XANA was playing a trick on him. The girl seemed surprised by that name.

"The only person that calls me that is my little brother Ulrich" She stated in shock. Ulrich then ran up to her giving her a hug.

"It really is you Nina" He said as he embraced her. That's when she realized that it was Ulrich. She returned the hug after it hit her that he was her brother.

"I missed you little brother" She mumbled to him. The two pulled apart. "Sorry, I should probably introduce myself. I'm Katrina Stern, some people call me Trina and only this one calls me Nina" She said as she placed her hand on her brother's head. The group introduced themselves to her and explained to Katrina what was going on. Ulrich was happy that after five years apart, he was finally reunited with his sister. The only problem was that she was stuck here on Lyoko.


	4. Chapter 3

After the tower was deactivated the group was devirtualized leaving Katrina on Lyoko all by herself. Ulrich was happy to finally be reunited with his sister after being apart for five years but was saddened to leave her alone on a virtual world.

"Do you think Code Earth will work on Nina?" Ulrich asked. Jeremy shook his head.

"Code Earth was designed specifically for Aelita. I would have to reprogram it using Katrina's DNA, but even then, it most likely wouldn't work. There are too many bugs in the program. She could wind up lost forever" Jeremie explained. Ulrich didn't like the sound of that. It was bad enough that she disappeared in the first place. Now there was a possible chance she might disappear forever. Ulrich balled his hands into a fist in frustration.

"It's okay Ulrich. We'll find a way to get Katrina back" Yumi reassured him placing her hand on his shoulder. Later that day, they all went to class. Jeremie, Ulrich, and Odd were in Miss Hertz's class. Ulrich was too distracted by the situation with his sister to pay attention to the lesson.

"Ulrich!" Miss. Hertz called on him.

"Huh?" He responded coming out of his daze.

"What's the answer to the question on the board?" She asked. Ulrich examined the question on the board. After some thought he couldn't come up with an answer.

"Uh...I don't know" He said giving up.

"Well maybe if you paid attention you would know" She stated sternly with a slight glare. She went back to teaching as she explained the answer to the question on the board.

"Hey, no need to be so glum. Jeremie said he was going to re-work the program later after school" Odd whispered to him.

"Uh huh" He responded not really paying attention. The bell rang dismissing the class. Ulrich went straight to his dorm not in the mood to be around other people. They just let him be for now. Odd and Jeremie went to the cafeteria to meet up with Yumi and Aelita, who were already sitting at the table eating their lunch. They got their food and sat down at their table.

"Where's Ulrich?" Yumi asked.

"He decided to go sulk alone" Odd replied.

"I guess he's really close to his sister since he's so upset" Aelita commented.

"Yeah he seemed so happy to finally see her again after being apart for five years" Yumi chimed.

"If I manage to get a hold of a sample of Katrina's DNA, I should be able to re-program Code Earth to work devirtualize her." Jeremie mentioned.

"How are we going to do that? It's not like Ulrich could just go home and find something in her room that would have any of Katrina's DNA on it" Odd commented.

"Wait, isn't Katrina's DNA already in the computer? Why can't we use that?" Aelita questioned remembering seeing Katrina's DNA sequence on the screen the other day.

"I might be able to use it if it's not corrupted by a virus, I'd like to get a backup sample just in case. If I use the same program I used to materialize Aelita's DNA, I should have no problem materializing a sample of Katrina's" He explained.

"So, are we going to head to the factory?" Yumi questioned.

"No not yet. I'll let you guys know once I'm done" Jeremie said. He finished his lunch and got up from the table. He threw out his garbage and headed to his dorm. Aelita met up with him after she finished.

The two were in Jeremie's dorm trying to figure out a way to materialize Katrina. Jeremie sat at his computer while Aelita sat on Jeremie's bed with the laptop. Jeremie tried to contact Katrina using the same method he used when Aelita was in her situation. Soon enough Katrina's face popped up on his screen.

"Hi, you must be Jeremie. It's nice to put face to voice" Katrina greeted with a soft smile.

"You know, you look nothing like Ulrich" Jeremie commented.

"Thanks for the compliment." She responded. Aelita placed the laptop down on the bed and got up from the bed walking over to the computer.

"How close were you and Ulrich before you got stuck on Lyoko?" Aelita asked.

"Well we had a typical sibling relationship. We fought a lot of little things, but for the most part we got along fine" She answered.

"Do you remember how you got stuck on Lyoko?" Jeremie asked. Katrina shook her head.

"No before I got here, I was an intern at a computer lab that was funded by the government" She told him.

"Do you remember who was in charge of the lab?" He asked. Katrina shrugged her shoulders.

"I'm not too sure, but I think his name was Dr. Franz Hopper or something" She replied. Both Jeremie and Aelita seemed surprised by this. Katrina used to work with Aelita's father.

"Well we just got our answer. Franz Hopper is the one who created Lyoko" Jeremie told her.

"He's also my father" Aelita mentioned.

"Oh, you're the daughter Dr. Hopper used to talk about. He mentioned that his goal was to create a world where he could keep his family safe" Katrina stated.

"Anyways, we're going to try and find a way to rematerialize you back on Earth. We need a favor from you though" Jeremie told her.

"What is it?" She asked.

"I need you to go to Sector Five and retrieve some data for me" Jeremie stated.

"Sector Five? I've never heard of that sector before. I only know of Forest, Desert, Ice, and Mountain sectors" She commented.

"Maybe I should go to Lyoko and take her there" Aelita suggested looking at Jeremie.

"It would be too risky for you to go by yourself" He noted.

"Excuse me, but I think I'm more than capable of acting as someone's escort" Katrina commented feeling offended.

"Well if you lose all your life points, you'll disappear forever" Jeremie mentioned.

"Yes, I'm well aware of that" Katrina commented.

"We could at least bring Ulrich. He's been acting all depressed since our last trip to Lyoko" Aelita then suggested.

"Ulrich is always like that though. I haven't seen my brother in a good mood since he started middle school" Katrina mentioned. "My father is partially to blame though if I were to be honest. He's always so hard on Ulrich especially when it comes to academics. If Ulrich got so much as a C on his report card, he was grounded, and I usually would be the one stuck tutoring him and if I refused, I would also get punished" She continued.

"That explains why he's so reluctant to go home" Aelita chimed.

"Anyways, I guess we could wait for Ulrich. I mean since I don't exactly know what to do in this Sector Five area it would make sense to have someone else there as back up" Katrina stated.

"Alright then, well do this tomorrow. I'll let Ulrich know what's going on" Jeremie stated.

"Okay, I'm gonna go, I think I hear some movement outside. I'm gonna go check it out" Katrina said before ending the video transmission.

"Do you think Ulrich is going to be up for it?" Aelita questioned.

"It involves his sister, so I don't see why not" He responded. Jeremie went back to re-coding the program after Aelita said her goodbyes and left for the night.


	5. Chapter 4

Things seemed quiet on Lyoko as far as Jeremie could tell. While talking to Jeremie last night, Katrina heard noise while inside a tower in the mountain sector and decided to go explore. After leaving the tower she looked around and didn't see anything out of the ordinary. In fact, there was nothing. Regardless, she pulled out her laser pistol just in case XANA was planning to lull her into a false sense of security. Her finger hovered over the trigger ready to shoot what might sneak up on her.

Meanwhile, back on Earth, things were much livelier compared to Lyoko. It was morning for them. Ulrich and Odd stood by the hot beverage vending machine as it dispensed Ulrich's hot chocolate. He seemed especially grumpy today. Maybe it was because there might be a chance that Katrina would never be re-materialized back on Earth.

"Hey Ulrich!" Someone called out to him. He turned his head noticing that Jeremie was approaching them. "I have a mission for you" Jeremie then mentioned.

"A mission?" Ulrich said confused. "What for?" He then questioned.

"I need you and Aelita to go to Lyoko and escort Katrina to Sector Five. We're going to try and materialize a sample of her DNA" Jeremie explained.

"Hey, how come I'm not invited?" Odd questioned feeling left out.

"You can go too. I figured it wouldn't raise any red flags for XANA if it was just three instead of the whole group. I didn't even tell Yumi about this plan" Jeremie noted.

"Well what happens if XANA launches an attack? Wouldn't either Aelita or Katrina have to leave Sector Five to go deactivate the tower?" Odd asked. "Plus, Katrina can't exactly get devirtualized or she'll be gone forever so wouldn't it be better for her to have more protection?" he then noted. Jeremie knew Odd had a point. There were so many variables to this mission that anything could easily go wrong at any moment.

"Odd and Yumi should come too. We can't risk my sister getting devirtualized." Ulrich chimed.

"I know we can't" Jeremie commented. Just then, his laptop started beeping. He took off his backpack and pulled out his laptop. After opening up the laptop, he saw the scanner had picked up an activated tower. "Well so much for our mission. Activated tower in the mountain sector" Jeremie informed the two. Both nodded their heads as they headed for the factory. On his way, Ulrich called Yumi to inform her of the activated tower and to head to the factory. Once the three of them were at the factory, Ulrich and Odd headed to the scanner room while Jeremie sat at the super computer. He called Aelita to let her know what was going on.

"Jeremie, what sector is my sister in?" Ulrich questioned after being virtualized onto Lyoko.

"I'm searching for her location right now" Jeremie stated as he was typing away on the keyboard. He eventually was able to pull up her location. "It says on the map that she's there in the mountain sector" He informed Ulrich. The two of them looked around and didn't see anyone else. Not even any of XANA's creatures.

"Uh Einstein, I hate to break it to ya, but she ain't here" Odd chimed.

"She's probably on her way to the tower. It's on the other side of the sector" Jeremie stated. "Vehicles are on their way" He added. With a simple code and a press of a button their vehicles were virtualized onto Lyoko. "Yumi and Aelita should be here soon" Jeremie then mentioned. Ulrich and Odd hopped onto their vehicles and headed for the other side of the mountain sector. From a distance Ulrich could see someone flying. He immediately assumed it was Katrina.

"Nina!" He called out to her using his nickname for her. She turned her head to see her younger brother riding on the overbike. While distracted, Katrina took a hit from a hornet and tumbled to the ground. "NINA!" He called out again only this time in worry. He pulled up beside her. "Are you okay?" He then asked.

"Ugh, yeah I'm fine" She replied as she got up off the ground dusting herself off. "Where are Yumi and Aelita?" She then asked.

"Jeremie said that they're on their way" He responded.

"Oh right, I heard him say something earlier, but I was trying to focus" She mentioned. "Hey Jeremie! Am I good on life points?" She asked calling out to the kid genius.

"Yeah, you only lost 10 life points so far. Try to be more careful please" He advised.

"Yeah uh huh" She responded. "You sound like my mother" She then mumbled.

"I heard that!" He voiced through the mic. The hornet that shot at Katrina came back around and fired again. This time it missed. Katrina pulled out her pistol and shot at the hornet. She landed a direct hit causing the hornet to explode.

"Well...so much for a clean run" She commented referring to the hornet. Just then Yumi and Aelita arrived. "Oh hey, you two just missed the fun" She added greeting the two girls. Both of them looked at her confused.

"Don't mind her, she's just salty cause she got hit by a hornet" Odd commented.

"I'm sorry, did you just call me salty?" Katrina questioned feeling insulted.

"You know, I was wondering how you and Ulrich were related, but now I see it. You two act the same" Odd stated.

"We do not!" Katrina and Ulrich shouted together.

"Can you guys focus. There's still a tower to deactivate" Jeremie reminded them.

"Yeah I'm well aware of that Einstein. In case you weren't aware there's freakin' hornets everywhere!" Katrina voiced in annoyance. She was right; More hornets appeared in swarms. Katrina sighed figuring this was going to require more firearms. "Hey Jeremie! I need a favor. Type in the code LP2" She then requested. Jeremie typed in the code not knowing what it was. Soon after a second laser pistol was virtualized in Katrina's hand.

"Wait, you can virtualize more weapons?" Odd questioned confused by what just happened.

"Yeah, you guys never knew that?" Katrina questioned in disbelief. They all shook their heads.

"I didn't know either" Jeremie chimed.

"Well it's a good thing that I knew then, but I don't know all the codes. I just know the codes for my armory" She commented. With both laser pistols in hand, Katrina took flight once again as she headed for the activated tower. Hornets shot at her with each shot missing as she managed to evade them. Soon, the tower was in their sights. Katrina went straight for the tower while the others fought off the monsters. However, a megatank rolled up and aimed for Katrina.

"Nina!" Ulrich called out alerting his sister. Unfortunately, it was too late. The megatank had fired and hit Katrina devirtualizing her. Ulrich watched in horror as his sister disappeared.

"Ulrich now is not the time to be upset. We have to get Aelita to the tower!" Yumi told him as she used her fan to protect herself from the cross fire. Odd destroyed the megatank that devirtualized Katrina. With the biggest threat gone, Aelita was able to get to the tower safely. Within minutes, the tower was deactivated and everyone was rematerialized.


	6. Chapter 5

After witnessing his sister's devitalization, Ulrich's behavior seemed to have gotten worse. He couldn't help but blame himself for what happened. When the group was rematerialized, they gathered around the super-computer watching Jeremie try and figure out what had happened to Katrina. Jeremie seemed perplexed that Katrina still appeared to be on Lyoko in a same area where she was supposedly devirtualized in.

"How is that possible?" Jeremie mumbled in disbelief.

"What's going on? Did you find her?" Ulrich questioned anxiously.

"I'm not sure. According to the data she's still in the mountain sector" He responded.

"How? We all watched her get taken out by a megatank" Odd noted.

"I don't know. I saw life points disappear so she should be gone, but somehow she survived" Jeremie stated. Then suddenly a transmission came through the computer. That's when Katrina appeared on screen.

"Hey guys" She greeted with a smile on her face. Ulrich pushed Jeremie aside to talk to Katrina.

"Nina! How did you manage to re-virtualize yourself?" Ulrich questioned. Katrina looked at him confused.

"What are you talking about? I was never devirtualized" She responded.

"But we saw you get destroyed by a megatank" Ulrich noted.

"Oh, so that's what happened" she muttered as she snapped her fingers. Everyone looked at her confused. Katrina noticed that they had no idea what she was even referring to. "I guess I should probably explain. I made a copy of myself and sent her out to check out the surrounding area and monitored from inside this tower" She explained.

"You can do that?" Ulrich questioned confused. Katrina nodded her head.

"Yeah, I'm not gonna risk losing all my life points if I don't know what's going on outside the tower" She told her younger brother.

"Nina! Why didn't you say anything before?!" Ulrich shouted through the screen. "I thought my sister was gone forever this time" He then said as his voice cracked slightly as if he was about to cry. Katrina saw that her brother was trying so hard to fight back tears and felt guilty for being the reason behind them.

"I'm sorry Ulrich" She said with a strand of guilt echoing in each word that left her mouth.

"How exactly did you make a copy of yourself?" Jeremie questioned. He was curious to know everything she was able to do on Lyoko.

"I used the code for it. I'm guessing since you're asking you've never read Franz Hopper's Journal?" She responded.

"Yeah, but the files were ruined during a XANA attack" He replied.

"You are aware that those files were backed up to the super computer. If they were corrupted in any matter, I'm sure you can still access them from within Lyoko. If I had to guess the information is probably stored in that sector you mentioned the other night" She stated.

"Well then I guess our next mission is to take Katrina to Sector Five and retrieve the files and find a way to re-materialize Katrina" Jeremie stated. Katrina's transmission ended after that. Ulrich sighed with relief knowing his sister was okay after all.

Later that night everyone was back in their dorms with the exception of Yumi whom returned home. Ulrich and Odd are still awake with Odd playing video games and Ulrich sitting on his bed flipping through the scrapbook. There were several pictures of him and his sister together when they were kids. One that stuck out to him was the picture their mom took of them when he won his very first pencak silat tournament. He smiled at the photo. Then his smile turned into a frown thinking that there was a possibility that they might not get to share moments like that anymore. He needed to find a way to bring her back. Tomorrow's mission is supposed to bring them one step closer. Odd looked up from his game for a moment to see the look on his roommate's face.

"Oh will you cheer up already. We're going to bring her back" He told him. Odd was getting slightly annoyed at Ulrich's bitterness.

"What happens if something goes wrong and Katrina ends up lost forever?" Ulrich questioned. He always had a habit of thinking negatively.

"Quit being so negative. Do you really want to convince your sister that there's no hope in bringing her back? She's not stupid you know. I think she can sense that you have no faith what so ever that this will work" Odd stated. Ulrich new he had a point. Although it wasn't that he had no faith. He did, he just didn't want to get his hopes up. He didn't say anything. It was mostly because he had nothing to say. Ulrich decided to call it a night as he closed the scrapbook placing it in the drawer under his bed before crawling underneath his sheets facing away from his roommate. Odd shrugged his shoulders returning to his game.


	7. Chapter 6

Morning had arrived. Ulrich woke up ready to go to Lyoko to go on this mission with his sister. Unfortunately, it had to wait until after the school day was finished. He got up, took a shower, got dressed, and headed to class with Odd. He noticed Ulrich was in better spirits compared to yesterday.

"Well, looks like someone is in a good mood today" Odd commented in a somewhat teasing tone. "I guess my little pep talk worked" He then commented as his hands clasped behind his head with a seemingly smug look on his face. Ulrich rolled his eyes at his roommate and continued walking. They eventually met up with Jeremie and Aelita who were waiting at the entrance to the classroom. Jeremie had a concerned look on his face which worried Ulrich.

"What's wrong Jeremie?" Ulrich asked. He hoped that this wasn't tied to the status of his sister's re-materialization.

"We hit a snag in the program to materialize a piece of Katrina's DNA. The program got bugged somehow so until I figure out a way to fix it. There's no chance of trying to materialize your sister anytime soon," Jeremie told him. Ulrich's good mood immediately changed back to his typical bitterness.

"So does that mean no mission?" Odd questioned. Ulrich was curious about this as well. Maybe there wasn't a point in going on this mission if it was doomed before they even got virtualized on to Lyoko. "The mission is still a go. After doing some research trying to get the program to work. I discovered that Katrina has more source codes than Aelita so she might be able to access more information in Sector Five," He responded.

"This mission is gonna be so cool!" Odd voiced hyped for when school was over and they could go to Lyoko. The four of them entered the classroom as the bell rang signaling the start of class. It was Ms. Hertz class, in typical fashion Jeremie, Aelita, and Herb were answering all the questions Ms. Hertz asked the class. Ulrich and Odd didn't bother to pay attention to the lesson being taught.

Later that day the bell rang dismissing the last class of the day. Ulrich was the first one to leave as he immediate shot up an sprinted out of the classroom the second he heard the bell rang. "Boy, I haven't seen Ulrich this anxious to be somewhere since Yumi started hanging out with William" Odd commented surprised by how fast Ulrich left. By the time the others left the classroom, Ulrich was already halfway to the factory. When he arrived, he heard his sister's voice through the supercomputer. He ran to the computer and put on the headset.

"Nina? Can you hear me?" He questioned speaking through the mic.

"Ulrich?" She responded not used to hearing his voice through the computer. He saw on the screen that she was in the desert sector being chased by a variety of monsters. "Please tell me that the others are on their way" She requested as she ran to the nearest tower to take escape the hoard.

"Yeah, they should be here any minute," He responded.

"Okay, please tell me you know how to virtualize yourself. I could really use some help right now" She sounded slightly panicked which worried Ulrich. Just then, the elevator door opened revealing the rest of the gang. Ulrich took off the headset and handed it over to Jeremie.

"We need to get to Lyoko quick. Trina's in trouble." Jeremie took Ulrich's place at the supercomputer as Ulrich entered the elevator with the others heading for the scanners.

"Katrina. It's Jeremie. The others are on their way," He spoke through the mic.

"Oh thank god," She breathed a sigh of relief. Just as the others were virtualized, Katrina got zapped by a hornet causing her to tumble to the ground. Ulrich, whom was just virtualized onto Lyoko witnessed this.

"Nina!" He exclaimed as he super sprinted to his sister. Katrina got up off the ground dusting herself off. Then he remembered something.

"You're not a clone are you?" He asked.

"No, I can only make one clone and it got taken out by a crab before you guys got here," She told her brother.

"You better be careful Katrina. That hornet took ten of your life points." Jeremie voiced. Katrina rolled her eyes in response. Worried about his sister, Yumi and Odd were left to defend Aelita from the monsters on their own.

"Hey Einstein, we could use some vehicles" Odd stated as he shot laser arrows at a group of the hornets. "Already on it" Jeremie said typing away at the computer. Soon the vehicles appeared on Lyoko. Unfortunately, there were only three.

"I'm starting to wish Hopper installed those upgrades before he disappeared," Katrina mumbled annoyed at the lack of vehicles.

"Sorry Katrina. I can only program one of each at a time," Jeremie stated. She groaned in response.

"Ulrich, I'm assuming the bike is yours?" She questioned turning to her younger brother.

"Yeah" He responded confused.

"Alright, I guess you and I are riding together then." She said as she hopped onto the overbike. Ulrich sat behind his sister holding on to her by her shoulders. The two rode off together. "You don't get motion sickness do you?" She then asked.

"No" He replied.

"Good" She commented as she revved the engine causing the bike to go faster. She managed to surpass the others. "Jeremie, where exactly am I going?" She then asked.

"To the edge of the sector" He responded. She wasn't sure why, but assumed he had a plan.

"Ulrich, how far are the monsters from us?" She asked her brother. He turned his head to look behind them.

"They're pretty far but I think they're gaining on us" He stated.

"What are they?" She inquired. She needed to know what monsters were following them before coming up with a plan.

"Crabs and tarantulas," He replied.

"Perfect" She said with a smirk. Sherevved the bike once again going faster than before. She then turned around and was driving straight into the hoard of monsters. The other three past them and was confused by what Katrina was doing. "Ulrich, when I give the go ahead. You need to jump off the bike as fast as you can." She stated.

"What are you planning Nina?" He questioned unsure of what was going on inside his sister's head.

"Just trust me will ya." She responded. As she was getting closer to the hoard of monsters that were initially chasing them she placed a small device on the side of the bike and told Ulrich to jump. Both Katrina and Ulrich jumped from the bike. As the bike reached the hoard, it exploded, destroying all the monsters in the vicinity. "Worth it" She commented knowing she destroyed the fastest way to the edge of the sector. "Did you just blow up all the monsters?" Ulrich questioned.

"Yup" She responded with a smirk. "It's a good thing I timed that perfectly cause that could've easily taken us out too" She added. The other three came back to them after witnessing the explosion.

"You know there's something satisfying about watching monsters explode," Odd commented.

"It's even more satisfying when you picture them as people you hate." She chimed.

"Need a ride?" Yumi offered Ulrich even though she had Aelita as her ride-along.

"Sure" Ulrich responded as he stepped onto the Over-wing.

"Jeremie, is it possible to re-program the overbike?" Katrina questioned.

"Sorry Katrina." He responded. Katrina sighed slowing regretting blowing up the bike. Then she realized something.

"Hey Odd. Can I ride with you?" She inquired. Unlike her brother, she wasn't afraid of heights and knew how to ride a skateboard.

"Well, of course! Who am I to deny a princess a ride?" He answered. Katrina rolled her eyes in response as she got on the overboard with Odd with one hand holding onto his shoulder. Her other hand clasped the handle of her laser pistol ready to pull it out of her holster if needed to. The group eventually reached the edge of the sector. Jeremie put in the code for the transporter which took them to Sector Five. When they arrived at Sector Five Katrina looked around. This place was familiar to her.

"You guys have been calling this place Sector Five? I've been calling it the Cortex," She stated.

"Cortex?" Aelita questioned.

"Yeah, cause this is where the core of Lyoko is located," Katrina mentioned.

"The core of Lyoko? I wonder if it's located in the same room as all the monsters" Jeremie questioned. Katrina just had a drained expression on her face. In her mind it was a stupid question. Of course the core is located in the same room as all the monsters. XANA is trying to destroy Lyoko after all so why wouldn't they be?


	8. Chapter 7

They were still in the room that the transporter dropped them off in. The walls opened up allowing them access to the rest of the sector. The group ran down the passageway into the next room that was set up like a maze. A countdown appeared on Jeremie's screen.

"Alright guys you have ten minutes to find the key" Jeremie announced.

"Key?" Katrina said confused. She had been here once before but she never knew anything about a key.

"There's a button we have to hit that lets us out of this room" Ulrich explained. Everyone looked around in an attempt to see if they could spot the key.

"Found it! Over there!" Yumi exclaimed as she pointed to where she spotted the key. Sure enough, there it was. All the way across the room sitting on the wall. It sounded like a simple task, but the path there was far from that. There were two ways to get to the key; going around the room which consisted of uneven platforms or to jump from platform to platform across the room when the platforms themselves are moving. As they were thinking about how to get to the key, the timer was counting down with now five minutes remaining.

"You guys better hurry up. You don't have much time left" Jeremie announced. Katrina decided with not much time left to just take the risk and jump across the moving platforms. She pressed a button on the heel of her boot that caused her feet to become energized. After that she took a running start and leaped onto one of the moving platforms.

"Nina be careful!" Her brother advised as he watched her jump from platform to platform. On the second one Katrina lost her balance, but luckily thanks to her shoes, she didn't fall. Ulrich felt both relieved and confused at the same time. He still had no clue what his sister was capable of here in Lyoko. "Two minutes left!" Jeremie voiced as he watched the timer dwindle down to zero. Katrina was halfway across from the key when something started shooting at her. She turned to her right to see a creeper off on the side.

"Jeremie! I thought you said all the monsters were in a different room!" She said now annoyed that she was going to have to dodge and jump her way across.

"They were. I guess Xana noticed you guys and sent creepers after you" He responded. Katrina groaned in response. She pulled out her laser pistol gripping it in her hand ready to shoot the creeper when she got the chance. However, another one appeared on her left and started shooting at her. She looked back at the rest of the group. Odd and Yumi were on their vehicles that Jeremie had programed trying to protect Katrina and Aelita from the laser beams. Aelita ran for cover and Ulrich just stood there and watched his sister worried that she might get devirtualized.

"Ulrich, instead of just standing there how about you help the others take out the creepers" She suggested although it wasn't really much of a suggestion. It was more of her being annoyed at her brother for just standing there when there was so much at risk at the moment. Ulrich nodded as he ran to one side with his sword held tightly in his hands ready to swing the second he gets close enough to one of the creepers.

"One minute left!" Jeremie exclaimed. There was panic in his voice. Now he wasn't so sure if they would make it with the sudden change in the situation. Odd managed to take out the creeper on Katrina's right with one of his laser arrows leaving only one creeper left as far as they can tell. Katrina hustled as she continued to jump across the platform. She eventually made it across and slammed her hand on the button deactivating the countdown with only mere seconds to spare. This caused another passageway to open up leading the group to the elevator that would take them to where they wanted to go. They ran through the passageway and hopped on the elevator as it rose taking them to the platform the central computer was on. Aelita played around with it first pulling data and sending it to Jeremie. Once again it was quiet. Not even a manta in sight. This didn't stop everyone from keeping their guard up. In fact, this caused them to be more alert. Once Aelita was done with her part, she switched with Katrina. This was her first time doing this even though she had been on Lyoko for a long period of time. Aelita watched from over Katrina's shoulder amazed by how much more information that had access to because of her. She wasn't sure exactly what information Jeremie wanted, so she sent him whatever she could find that would be of use to him.

"Alright Katrina, I think I got what I need for now" Jeremie voiced. He looked over the data that was sent to him. "Right now, go see what's going on in that room full of monsters" He then advised. Ulrich hopped on the overwing with Yumi. Aelita activated her wings. Odd approached Katrina on his overboard.

"Excuse me M'lady, would you like a ride?" Odd offered as he playfully bowed to her. Katrina smirked as a small giggled escaped her lips.

"I guess I can't say no can I?" She responded as she stepped onto the overboard holding onto Odd by his shoulders. Katrina was already prepared for what was ahead. Although she found it interesting that Xana was trying to destroy the core. Maybe Xana knew something that she didn't. For all they know, Xana had a way to free itself and no longer needed Lyoko. If not then this was a suicide mission. By destroying the core, not only would it wipe out Lyoko, but it would wind up eliminating Xana itself as well.

**A/N: Sorry I haven't updated this story in such a long time. I've been really busy and hadn't really had time to sit down and write lately. I'm already in the process of writing out the next chapter so you won't have to wait long again.**


	9. Chapter 8

The entire team ended up getting wiped out leaving Katrina behind. Right now, she was alone in a room filled with monsters. They all watched the screen of the supercomputer in anticipation. Ulrich being the most nervous out of them all. It was nighttime now and everyone needed to be back on campus by curfew. Yumi needed to get back home before her parents would become suspicious of her. Jeremie decided just to monitor the situation from his computer in his dorm room. As far as they were sure Katrina was still in the cortex. Later that night, they were all back in their dorms. Ulrich, Odd, Aelita, and Yumi were asleep. Jeremie was up on his computer. Right now, he was going through the data that Aelita and Katrina had collected for him. So far none of it seemed beneficial. Katrina was about to unlock more information with her unique source codes, but it still got them nowhere in her rematerialization. Eventually Jeremie decided to call it a night and go to bed. During the night something strange happened. On the screen of the supercomputer it showed that Katrina had been devirtualized and disappeared off the map. Soon the scanner started beeping indicating that a tower had been activated. Unfortunately, Jeremie was now in a deep slumber and didn't hear the tower scanner go off.

The next morning there was a knock on Ulrich and Odd's door. The knocking woke the both of them up. Ulrich rubbed his eyes as he sat up in his bed. He looked over at the clock on his nightstand which read 9:30am. Ulrich groaned as he got up out of bed as the knocking continued. He opened the door revealing Jim on the other side.

"Stern. You're wanted in the principal's office" He announced before walking away. Ulrich was confused by this. He looked over at Odd assuming he did something and framed him for it so he wouldn't get into any more trouble. Although the look on his face showed that he had no idea what was going on either. After getting ready for the day, Ulrich headed to the principal's office while Odd went to the cafeteria to get breakfast. In typical Odd fashion, he also ate Ulrich's serving of breakfast. When Ulrich arrived at the office he was surprised to see his parents and…..Katrina? His jaw dropped at the sight of his sister. The questioned he wanted to ask her but knew he couldn't was how she was able to rematerialize herself.

"Ulrich dear isn't this amazing?" His mother asked her son with a big smile on her face.

"But….how?" Ulrich uttered not sure of what else to say.

"She came home last night. She was able to escape from her kidnappers" His mom stated.

"We knew how much you missed your sister, so we came to visit you. Figured it was best to tell you the good news in person" His father spoke. In the first time in years since Katrina's disappearance, there was a smile on his parent's faces. Ulrich didn't seem to buy it. He was just with his sister last night on Lyoko and now she's standing in front of her here in the school. Katrina held her arms out wide inviting her little brother to hug her.

"I've missed you Ulrich" She said. Ulrich decided to play along for now until he could find out what was really going on. Ulrich's parents decided to pull Ulrich out of school for the day to celebrate Katrina returning home. They were back home. Ulrich observed Katrina as she walked around the house. So far, nothing seemed off about her as far as he could tell. Katrina then requested to go for a walk. Her parents were a bit skeptical at first since she had been gone for years and only just returned home. Despite that, they let her go once she convinced them that she was going to be fine and have her cell phone on her at all times. As much as Ulrich wanted to follow her, he was told by his father to stay home. Katrina returned two hours later just in time for lunch. When they were sitting at the table together as a family for the first time in five years Ulrich's phone started to go off. He pulled his phone out of his pocket and saw Jeremie's name on the screen. It's funny cause he actually thought about calling Jeremie.

"Excuse me, I need to use the bathroom" Ulrich announced as he got up from the table. He knew that if he answered the phone at the table, his father would scold him. When he got into the bathroom, he locked the door before answering the call.

"Yeah Jeremie, what's up?" Ulrich spoke into his phone.

"Activated tower in the mountain sector" He responded.

"Activated tower huh… now this makes sense" Ulrich mumbled.

"Huh? What do you mean? Has Xana launched an attack" Jeremie questioned.

"I guess you can say that. You're not gonna believe who is in my house right now" Ulrich commented

"Who?" Jeremie asked in response.

"My sister" He told him.

"Wha? That's impossible. I haven't even figured out how to re-materialize her yet" Jeremie stated. Ulrich could hear Jeremie typing away at the keyboard of the supercomputer. "Wait a second. Maybe you're right. It looks as if Katrina disappeared from Lyoko. I can't find her anywhere on the map." He continued.

"What should we do? She's not really behaving out of the ordinary." Ulrich spoke.

"We'll worry about her later. Right now, we need you at the factory" Jeremie stated.

"Alright. I'll see what I can do" Ulrich said before hanging up. He let out a heavy sigh before unlocking and exiting the bathroom. He went back into the dining room where his family still sat.

"Hey Mom, can you take me back to school? I left something in my dorm that I want to show Nina" Ulrich requested.

"Sure dear, let me just grab my purse" His mom said as she wiped her mouth with her napkin before excusing herself from the table. She grabbed her bag and a set of keys before heading out with Ulrich. After a few minute drive, the two arrived at the school. Ulrich got out of the car.

"Just wait here, I'll be right back" He told his mother as he left her behind and ran towards the school. He made a turn running into the forest and to the sewer that led straight to the factory. After a short skateboard ride, Ulrich arrived at the entrance to the factory. He swung down the rope into the elevator heading straight to where Jeremie was. Upon arrival he was greeted not only by Jeremie, but by Odd, Aelita, and Yumi. This confused him. If there was an activated tower, the three of them should already be on Lyoko.

"What's going on? Why aren't you guys on Lyoko already?" Ulrich asked.

"Someone pulled out the cords to the scanners so they're offline" Aelita replied.

"You don't think it could be Trina could it?" Ulrich questioned. He knew his sister was alone for at least two hours. That was plenty of time for her to get to the factory, unplug the scanners and come home.

"It's possible if she's under Xana's control" Aelita responded.

"Can't we just plug them back in and restart the scanners?" Odd questioned.

"I think that's our only option at the moment"


	10. Chapter 9

With the scanners plugged back in and back online, the warriors were virtualized onto Lyoko. They arrived in the mountain sector with monsters waiting for them. A group of bloks and hornets at the ready which typically meant that Xana was already one step ahead. Unfortunately for them, the activated tower was on the other side of the hoard. Ulrich, who was determined to save his sister charged right in deflecting every laser that was shot at him with some ricocheting off his blade and back at the monster instantly destroying them. Odd hoped on his overboard and shot his laser arrows at the hornets. Yumi stayed with Aelita to protect her. Jeremie tried hard to track down Katrina on his end but came up empty-handed. Maybe it was possible that Katrina was re-materialized. The warriors eventually defeated all the monsters narrowly making it out without anyone getting devirtualized. That's when something appeared on the map.

"Wait, I see something heading your way" Jeremie alerted the group. The four of them were cautious not knowing what to expect. The thing that Jeremie mentioned had came into view and turned out to be Katrina sprinting her way to the group.

"Nina!" Ulrich called out to his sister as he ran to her. The other three followed Ulrich. There was something off about Katrina however, she was very cautious around them even though she was familiar with them of course one being her younger brother.

"I'm sorry to disappoint you, but I'm not the real Katrina. I'm just a clone. Katrina was captured and his trapped somewhere in the cortex. Xana made another copy of her and sent it to the real world to destroy the supercomputer" She told them.

"I knew that couldn't be the real Trina" Ulrich mumbled to himself.

"So, you're saying we need to get to sector five and rescue Katrina" Aelita commented. The clone shook her head.

"Xana is using the energy from the activated tower here in the mountain sector to hold Katrina. Once that tower is deactivated, Xana won't be able to hold her hostage any longer thus freeing Katrina" She explained.

"So then let's deactivate the tower" Odd suggested.

"Uh guys, there's a small problem. The tower is surrounded by mega-tanks" Jeremie stated as he looked over the map. Ulrich rolled his eyes figuring rescuing his sister wasn't going to be easy. When they arrived, it was just like Jeremie said. The activated tower was completely surrounded by mega-tanks. They were considered the most annoying monster since they were difficult to take down. Katrina's clone decided to make the sacrifice and take out the mega-tanks herself.

"I'll take care of the mega-tanks. You guys just cover Aelita making sure she gets into the tower" She told them as she took out her laser pistol before jumping out of her hiding place. One of the mega-tanks sensed her presence and started firing up. She managed to shoot the mega-tank destroying it before it could actually fire. This caught the attention of the other mega-tanks as they rolled away from their positions and towards Katrina's clone. The group took advantage of this and started heading for the tower. Katrina's clone managed to take out another mega-tank leaving only two. Unfortunately, she was devirtualized when a single hornet snuck up on her. Ulrich happened to witness this and cringed at the sight. He was well aware that it wasn't really his sister but watching her get taken out by a hornet hurt just as much. Aelita made it into the tower with the help of the others. She went up to the second level pressing her hand on the screen being granted access to type in the code to deactivate the tower. Once the tower was deactivated the spectre of Katrina in the real world disappeared and the real Katrina was released from the barrier that Xana had locked her in inside Sector Five.

"Jeremie, can we just do a return to the past, so I don't have to explain to my parents that Katrina is gone again?" Ulrich requested. His parents were so happy to see their daughter return and it would break their heart knowing that it wasn't really her and the real Katrina was still stuck on Lyoko.

"Already on it" Jeremie said as he programed and initiated the return to the past. After that the group met up with Jeremie in his dorm room as he sat at the computer typing away at his keyboard.

"For once Xana actually did something beneficial" Jeremie commented.

"How so?" Yumi questioned.

"When Ulrich told me that Katrina had been re-materialized, I did some digging. I managed to find the code that Xana used to make a copy of Katrina and materialize her. If I rework that code, I might be able to rematerialize the real Katrina" Jeremie stated as he turned around fixing his glasses with his index finger.

"Does that mean we need to go back to Sector Five?" Odd asked.

"Well, I am going to need more data so yes. According to the map Katrina is still in sector five so if I can get her to access the computer there and extract the data, we need we'll be one step closer to bringing her back" Jeremie responded. Ulrich eyes lit up when he realized that soon he was going to have his sister back for real this time. While it was nice having a mere copy here on Earth. He knew that it was a sign that his actual sister was now even closer to coming home.

**A/N: Just a heads up, the next chapter will be delayed until the end of the month. I'm aiming to have it released by October 27****th****.**


	11. Chapter 10

With a return to the past, no one recalled the return of Katrina Stern. Jeremie sat at his computer all night trying to figure out the proper code that Xana used during his last attack that would successfully bring Katrina back to the real world. She was still in Sector Five and able to access the computer sending more data to Jeremie. The two were able to communicate even from his computer in his dorm room.

"I honestly can't believe Xana would be cruel enough to send a copy of me to the real world and trick my family into thinking that I've returned" Katrina grumbled. "I believe it. Xana will do anything to get his way" Jeremie commented.

"Yeah, I guess that's true" She responded as she was tapping at the screen moving data around. "I hope Ulrich is okay though. He must have been so devastated" She continued.

"Actually, he's the one who figured out that it was a spectre. All we knew was that there was an activated tower. When I called Ulrich, he said that you had returned home. I'm sure he was suspicious right from the beginning" Jeremie commented.

"Yeah, but still. I know he's been dying to have me back in the real world for a long time. My parents too for that matter" She responded.

"Don't worry, after I rework this code we'll have you back on Earth in no time" Jeremie told her trying to assure her that everything is okay.

"You know Jeremie, I'm glad that my brother has good friends like you. Thank you" she said with a smile on her face even though Jeremie couldn't see her he could tell by the tone of her voice that she was in better spirits now. "Hey, do you think this will be working by Ulrich's birthday? We could surprise him" She then suggested.

"Oh that's right. His birthday is next week. I should have the program ready by then" Jeremie responded.

"I hope this works out. I've been gone for five years from what I've been told." She commented. "Unfortunately, that means I owe Ulrich like five years of pencak silat lessons" She then mumbled. Jeremie chuckled knowing she was right. The two ended their communication. From there on, Jeremie worked tirelessly trying to rework the code to bring back Katrina. He wound up skipping his morning class since he stayed up all night on his computer. Odd covered for him saying that he was sick. The bell rang dismissing the class. Odd, Ulrich, and Aelita met up outside waiting for Jeremie and Yumi to show up.

"What's Einstein even up to? It's not like him to miss science" Odd questioned. "He's still trying to replicate the code that Xana used to materialize a copy of Katrina" She responded.

"Has he made any progress?" Ulrich inquired. Aelita shrugged his shoulders.

"I haven't spoken to him since the last time we went to Lyoko to rescue your sister" She replied. "Supposedly he's working with her to gather more data from Sector Five" She then added.

"Hey, maybe she'll be rematerialized by your birthday Ulrich" Odd commented as he gave his roommate a pat on the back. Just then Yumi showed up.

"Hey, how's everything going? Where's Jeremie?" She greeted as she walked up to the group.

"He's in his room working on the rematerialization code for Katrina" Aelita responded.

"Yeah, we were talking about the possibility of Katrina being rematerialized in time for Ulrich's birthday" Odd chimed in.

"Oh well, that would be a cool birthday present" Yumi commented.

"Yeah, but I doubt it would happen. I mean it took almost a year before we were finally able to materialize Aelita so" Ulrich said with a sliver of doubt in his voice.

"Well thanks to Xana we're now much closer to bringing her back" Aelita noted.

"Yeah that's true. If it wasn't for Xana's last stunt, we'd be sitting at a dead-end right now" Odd commented. Ulrich knew the two of them had a point.

A week had passed by and it was the night before Ulrich's birthday. Jeremie, Aelita, and Yumi were at the factory. Jeremie had managed to get the code to work. As Katrina requested, they kept her materialization a surprise from Ulrich. Odd's job was to bring Ulrich to the factory once Katrina was successfully rematerialized. Yumi and Aelita waited downstairs in the scanner room as Jeremie entered the code. Soon enough Katrina appeared in the center scanner. She seemed like she was in a daze and even stumbled out of the scanner.

"You okay Trina?" Yumi asked concerned that maybe something went wrong in the materialization.

"Yeah I'm fine, no need to worry" She said. "I'm not used to this". The three of them went upstairs to the supercomputer so Katrina could meet Jeremie in person.

"You must be Jeremie. You look exactly how I imagined actually" Katrina commented. Yumi and Aelita giggled in response.

"Welcome back to Earth Katrina" Jeremie greeted.

"Well, so far it's good to be back" She responded.

"Ulrich's going to be so happy to see you. He's been in a funk lately" Aelita told her.

"This is Ulrich we're talking about. He's always in a funk." Katrina noted.

"Yeah that's true" Yumi chimed.

"Anyways, since it's late, the plan is to surprise Ulrich in the morning" Jeremie stated.

"What are we going to do? I can't just go home. My parents are gonna interrogate me and probably won't let me leave afterwards" Katrina mentioned.

"Don't worry, it's all taken care of." Yumi said as she placed her hand on Katrina's shoulder. "I'll told my parents that I was having a friend sleep over tonight so you can sleep at my house tonight" She explained.

"Oh, okay" Katrina responded. That night, Jeremie and Aelita went back to their dorms while Katrina followed Yumi to her house.

"So what exactly is the plan to surprise Ulrich anyway?" Katrina asked.

"Well Odd's job is to escort Ulrich to the factory. We thought about blindfolding him but we figured that would make it too obvious so Aelita came up with the idea of pretending to go to Lyoko and having you stand inside one of the scanners" She answered.

"Oh, that's a neat idea although something tells me he might think I'm another clone" Katrina commented. Yumi giggled knowing that was a possibility.

"Have you thought about what you're going to do now that you're back?" Yumi questioned. Katrina shrugged her shoulders.

"Well, I mean I kinda owe Ulrich like five years' worth of pencak silat lessons. Other than that, I'm not sure. Eventually I'll have to re-enroll in college" She responded. The two finally reached Yumi's house. Her parents were still up and greeted the girls as they entered the house.

"Thank you for letting me stay the night Mister and Misses Ishiyama" Katrina spoke as she slightly bowed to them.

"It's our pleasure dear. We're just glad that you're okay. Your parents must be worried about you" Yumi's mom said.

"Probably, I plan on contacting them in the morning" She told her. The two of them went up to Yumi's room. A spare bed was already set up for Katrina. Yumi gave Katrina a change of clothes to sleep in. "So let me ask you something. Now that you're rematerialized would you ever consider going back to Lyoko?" Yumi asked. Katrina shrugged her shoulders.

"I honestly don't know. I mean I guess I should at least help you guys defeat Xana, but part of me is angry at the fact that being on Lyoko for such a long time has taken so much from me." She replied.

"Yeah, I guess you have a point" Yumi commented. "I wouldn't blame you for wanting to never go back" She continued. Eventually the two girls went to sleep.

Morning had finally arrived and everyone minus Odd and Ulrich were at the factory. The four of them were gathered around the supercomputer. "So Katrina, did you enjoy your first night back on Earth?" Aelita inquired.

"Yeah, it's gonna take some time to readjust but I'll get the hang of it soon" She responded.

"It took some time for me to adjust to life here too, so I understand" Aelita commented.

"Jeremie, would Katrina be able to get virtualized and materialized like the rest of us?" Yumi asked.

"Yes, I designed the code so Katrina can not only be rematerialized back onto Earth but can be virtualized and devirtualized like you four' He answered as he adjusted his glasses. Before Katrina could say anything Aelita phone pinged. She pulled out her phone which had a notification on her screen indicating a new message from Odd.

"Odd says he and Ulrich are on their way" She announced as she read the message. Yumi went down to the scanner room with Katrina to get in place for the surprise. Katrina got into the center scanner and the doors closed in front of her. Meanwhile, Odd and Ulrich just entered the factory.

"Did Jeremie mention what this mission is for? It's kinda weird going to Lyoko when Xana hasn't launched and attack" Ulrich inquired. Odd tried his best to keep Ulrich in the dark about what was going on. All he told Ulrich when he said that they had to go to the factory was because Jeremie needed them for a mission.

"No, he wouldn't say" Odd responded not being able to come up with a better cover. The two went down to the elevator to the scanner room where Aelita, Yumi, and even Jeremie waited for them. Ulrich was confused to why Jeremie was in here and not at the supercomputer.

"What's going on?" Ulrich asked.

"Nothing, just a routine trip to Lyoko" Jeremie told him.

"Then why are you down here?" He continued to question.

"The scanners were malfunctioning, so I came down to check on them" Jeremie lied. He had a countdown set up on the computer to open the doors to the scanner once it got to zero. Odd pushed Ulrich in front of the center scanner, the one that Katrina was hiding in.

"Hey! What the heck Odd?" Ulrich exclaimed confused on why Odd was pushing him. The countdown finally hit zero and the scanner doors opened up revealing Katrina. Ulrich's eyes widened at the sight of his sister standing in front of him inside the scanner.

"Nina?" He called out to her unsure if it was actually her or another clone sent by Xana.

"Hi Ulrich. I promise I'm not a spectre or any other of Xana's minions" she greeted as she exited the scanner. "Happy Birthday" She then said with a smile on her face. A tear trickled down Ulrich's cheek as he lunged forward pulling his sister into a hug.

"Best birthday ever" he muttered causing his sister to giggle as she returned the hug. It took five years, but he finally got his real sister back.

**A/N: Surprise! I finished the chapter early! This is actually the last chapter of this book but don't worry This book is only part 1 in a 2 part series. The first chapter of part 2 will be released sometime in December. Thank you for reading and supporting this story so far!**


	12. Part 2 Sneak Peak Release Date

Thank you for all the love on this story and for being patient with me. As a reward I decided to treat everyone to a small sneak peak of a chapter of Part 2 which will be titled "Sword & Pistol"

* * *

_A mission gone wrong left Ulrich stranded on Lyoko. To the warrior's surprise, Katrina showed up at the factory._

"_What are you doing here Katrina?" Aelita asked._

"_Send me to Lyoko" She demanded. The look on her face showed she was serious. Jeremie and Aelita were taken back by this._

"_Are you sure? I thought you never wanted to go back" Jeremie questioned. Katrina hadn't returned to Lyoko since she was rematerialized several months ago. At first, she was open to going back and helping them defeat XANA, but as time went on hatred for the virtual world built up and she vowed never to return._

"_I'll be honest. Even though I made a promise to never go back to Lyoko. I'm willing to break that promise knowing that my brother is in danger"_

* * *

First chapter will be release **November 29th**


	13. Sword & Pistol Release Announcment!

Hello Everyone!

Part 2 of "Code:Katrina" titled "Sword & Pistol" Has been officially released!

There is only 1 chapter as of right now. New chapters will be released **BIWEEKLY!**

With that being said. I hope you all enjoy part 2 :)


End file.
